In the manufacture of an electronic device such as a semiconductor device, an etching target film of a target object is etched by plasma etching. In the plasma etching, the target object is placed on an electrostatic chuck of a stage provided within a chamber main body of a plasma processing apparatus. Then, a processing gas is supplied into a chamber, and plasma is generated as the processing gas is excited.
The etching target film to be etched in the plasma etching may be, for example, a silicon oxide film, a silicon nitride film, or a multilayered film composed of these films. In the plasma etching of the etching target film such as the silicon oxide film, the silicon nitride film or the multilayered film of these films, a processing gas containing either or both of a fluorocarbon gas and a hydrofluorocarbon gas is used. For example, described in Patent Document 1 is a technique of etching a silicon oxide film by plasma of a processing gas containing a fluorocarbon gas.
Patent Document 1: Japanese Patent Laid-open Publication No. H10-116822
In the plasma etching of the etching target film such as the silicon oxide film, the silicon nitride film or the multilayered film of these films, if a temperature of the target object is low, an etching rate of the etching target film may be increased. Accordingly, the plasma etching may be performed in a state that the electrostatic chuck and the target object are set to a low temperature. If the plasma etching using the processing gas containing either or both of the fluorocarbon gas and the hydrofluorocarbon gas is performed, a plasma product containing carbon or containing carbon and fluorine is generated. This plasma product is condensed or coagulated at a low-temperature place, forming a deposit thereon. Thus, an unnecessary deposit is formed on the target object during a time period from a time point when the plasma etching is completed until a time point when the target object is carried out of the chamber.